yawanng updated this revision to Diff 109778.
yawanng marked 13 inline comments as done.
https://reviews.llvm.org/D35372
Files:
clang-tidy/android/AndroidTidyModule.cpp
clang-tidy/android/CMakeLists.txt
clang-tidy/android/CloexecCheck.cpp
clang-tidy/android/CloexecCheck.h
clang-tidy/android/CloexecMemfdCreateCheck.cpp
clang-tidy/android/CloexecMemfdCreateCheck.h
docs/ReleaseNotes.rst
docs/clang-tidy/checks/android-cloexec-memfd-create.rst
docs/clang-tidy/checks/list.rst
test/clang-tidy/android-cloexec-memfd-create.cpp
Index: test/clang-tidy/android-cloexec-memfd-create.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/android-cloexec-memfd-create.cpp
@@ -0,0 +1,63 @@
+// RUN: %check_clang_tidy %s android-cloexec-memfd-create %t
+
+#define MFD_ALLOW_SEALING 1
+#define __O_CLOEXEC 3
+#define MFD_CLOEXEC __O_CLOEXEC
+#define TEMP_FAILURE_RETRY(exp) \
+ ({ \
+ int _rc; \
+ do { \
+ _rc = (exp); \
+ } while (_rc == -1); \
+ })
+#define NULL 0
+
+extern "C" int memfd_create(const char *name, unsigned int flags);
+
+void a() {
+ memfd_create(NULL, MFD_ALLOW_SEALING);
+ // CHECK-MESSAGES: :[[@LINE-1]]:39: warning: 'memfd_create' should use MFD_CLOEXEC where possible [android-cloexec-memfd-create]
+ // CHECK-FIXES: memfd_create(NULL, MFD_ALLOW_SEALING | MFD_CLOEXEC)
+ TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_ALLOW_SEALING));
+ // CHECK-MESSAGES: :[[@LINE-1]]:58: warning: 'memfd_create'
+ // CHECK-FIXES: TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_ALLOW_SEALING | MFD_CLOEXEC))
+}
+
+void f() {
+ memfd_create(NULL, 3);
+ // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: 'memfd_create'
+ // CHECK-FIXES: memfd_create(NULL, 3 | MFD_CLOEXEC)
+ TEMP_FAILURE_RETRY(memfd_create(NULL, 3));
+ // CHECK-MESSAGES: :[[@LINE-1]]:42: warning: 'memfd_create'
+ // CHECK-FIXES: TEMP_FAILURE_RETRY(memfd_create(NULL, 3 | MFD_CLOEXEC))
+
+ int flag = 3;
+ memfd_create(NULL, flag);
+ TEMP_FAILURE_RETRY(memfd_create(NULL, flag));
+}
+
+namespace i {
+int memfd_create(const char *name, unsigned int flags);
+
+void d() {
+ memfd_create(NULL, MFD_ALLOW_SEALING);
+ TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_ALLOW_SEALING));
+}
+
+} // namespace i
+
+void e() {
+ memfd_create(NULL, MFD_CLOEXEC);
+ TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_CLOEXEC));
+ memfd_create(NULL, MFD_ALLOW_SEALING | MFD_CLOEXEC);
+ TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_ALLOW_SEALING | MFD_CLOEXEC));
+}
+
+class G {
+public:
+ int memfd_create(const char *name, unsigned int flags);
+ void d() {
+ memfd_create(NULL, MFD_ALLOW_SEALING);
+ TEMP_FAILURE_RETRY(memfd_create(NULL, MFD_ALLOW_SEALING));
+ }
+};
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -6,6 +6,7 @@
.. toctree::
android-cloexec-creat
android-cloexec-fopen
+ android-cloexec-memfd-create
android-cloexec-open
android-cloexec-socket
boost-use-to-string
Index: docs/clang-tidy/checks/android-cloexec-memfd-create.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/android-cloexec-memfd-create.rst
@@ -0,0 +1,18 @@
+.. title:: clang-tidy - android-cloexec-memfd-create
+
+android-cloexec-memfd-create
+============================
+
+``memfd_create()`` should include ``MFD_CLOEXEC`` in its type argument to avoid
+the file descriptor leakage. Without this flag, an opened sensitive file would
+remain open across a fork+exec to a lower-privileged SELinux domain.
+
+Examples:
+
+.. code-block:: c++
+
+ memfd_create(name, MFD_ALLOW_SEALING);
+
+ // becomes
+
+ memfd_create(name, MFD_ALLOW_SEALING | MFD_CLOEXEC);
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -73,6 +73,12 @@
Checks if the required mode ``e`` exists in the mode argument of ``fopen()``.
+- New `android-cloexec-memfd_create
+ <http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-memfd_create.html>`_ check
+
+ Checks if the required file flag ``MFD_CLOEXEC`` is present in the argument of
+ ``memfd_create()``.
+
- New `android-cloexec-socket
<http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-socket.html>`_ check
Index: clang-tidy/android/CloexecMemfdCreateCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/android/CloexecMemfdCreateCheck.h
@@ -0,0 +1,35 @@
+//===--- CloexecMemfdCreateCheck.h - clang-tidy-----------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_MEMFD_CREATE_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_MEMFD_CREATE_H
+
+#include "CloexecCheck.h"
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+/// Finds code that uses memfd_create() without using the MFD_CLOEXEC flag.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-memfd-create.html
+class CloexecMemfdCreateCheck : public CloexecCheck {
+public:
+ CloexecMemfdCreateCheck(StringRef Name, ClangTidyContext *Context)
+ : CloexecCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_MEMFD_CREATE_H
Index: clang-tidy/android/CloexecMemfdCreateCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/android/CloexecMemfdCreateCheck.cpp
@@ -0,0 +1,29 @@
+//===--- CloexecMemfdCreateCheck.cpp - clang-tidy--------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CloexecMemfdCreateCheck.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+void CloexecMemfdCreateCheck::registerMatchers(MatchFinder *Finder) {
+ registerMatchersImpl(Finder, returnsInteger(), hasName("memfd_create"),
+ hasCharPointerTypeParameter(0), hasIntegerParameter(1));
+}
+
+void CloexecMemfdCreateCheck::check(const MatchFinder::MatchResult &Result) {
+ insertMacroFlag(Result, "MFD_CLOEXEC", /*ArgPos=*/1);
+}
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/android/CloexecCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/android/CloexecCheck.h
@@ -0,0 +1,137 @@
+//===--- CloexecCheck.h - clang-tidy-----------------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the declaration of the CloexecCheck class, which is the
+/// base class for all of the close-on-exec checks in Android module.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+/// \brief The base class for all close-on-exec checks in Android module.
+/// To be specific, there are some functions that need the close-on-exec flag to
+/// prevent the file descriptor leakage on fork+exec and this class provides
+/// utilities to identify and fix these C functions.
+class CloexecCheck : public ClangTidyCheck {
+public:
+ CloexecCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+
+protected:
+ /// Currently, we has three types of fixes.
+ ///
+ /// Type1 is to insert the necessary macro flag in the flag argument. For
+ /// example, 'O_CLOEXEC' is required in function 'open()', so
+ /// \code
+ /// open(file, O_RDONLY);
+ /// \endcode
+ /// should be
+ /// \code
+ /// open(file, O_RDONLY | O_CLOEXE);
+ /// \endcode
+ void insertMacroFlag(const ast_matchers::MatchFinder::MatchResult &Result,
+ const StringRef MarcoFlag, const int ArgPos);
+
+ /// Type2 is to replace the API to another function that has required the
+ /// ability. For example:
+ /// \code
+ /// creat(path, mode);
+ /// \endcode
+ /// should be
+ /// \code
+ /// open(path, O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, mode)
+ /// \endcode
+ void replaceFunc(const ast_matchers::MatchFinder::MatchResult &Result,
+ StringRef WarningMsg, StringRef FixMsg);
+
+ /// Type3 is also to add a flag to the corresponding argument, but this time,
+ /// the flag is some string and each char represents a mode rather than a
+ /// macro. For example, 'fopen' needs char 'e' in its mode argument string, so
+ /// \code
+ /// fopen(in_file, "r");
+ /// \endcode
+ /// should be
+ /// \code
+ /// fopen(in_file, "re");
+ /// \endcode
+ void insertStringFlag(const ast_matchers::MatchFinder::MatchResult &Result,
+ const char Mode, const int ArgPos);
+
+ /// Helper function to get the spelling of a particular argument.
+ StringRef getSpellingArg(const ast_matchers::MatchFinder::MatchResult &Result,
+ int N) const;
+
+ ast_matchers::internal::Matcher<FunctionDecl> hasIntegerParameter(int N) {
+ return ast_matchers::hasParameter(
+ N, ast_matchers::hasType(ast_matchers::isInteger()));
+ }
+
+ ast_matchers::internal::Matcher<FunctionDecl>
+ hasCharPointerTypeParameter(int N) {
+ return ast_matchers::hasParameter(
+ N, ast_matchers::hasType(ast_matchers::pointerType(
+ ast_matchers::pointee(ast_matchers::isAnyCharacter()))));
+ }
+
+ ast_matchers::internal::Matcher<FunctionDecl>
+ hasSockAddrPointerTypeParameter(int N) {
+ return ast_matchers::hasParameter(
+ N,
+ ast_matchers::hasType(ast_matchers::pointsTo(ast_matchers::recordDecl(
+ ast_matchers::isStruct(), ast_matchers::hasName("sockaddr")))));
+ }
+
+ ast_matchers::internal::Matcher<FunctionDecl>
+ hasSockLenPointerTypeParameter(int N) {
+ return ast_matchers::hasParameter(
+ N, ast_matchers::hasType(ast_matchers::pointsTo(
+ ast_matchers::namedDecl(ast_matchers::hasName("socklen_t")))));
+ }
+
+ ast_matchers::internal::Matcher<FunctionDecl> hasMODETTypeParameter(int N) {
+ return ast_matchers::hasParameter(
+ N, ast_matchers::hasType(
+ ast_matchers::namedDecl(ast_matchers::hasName("mode_t"))));
+ }
+
+ ast_matchers::internal::Matcher<FunctionDecl> returnsInteger() {
+ return ast_matchers::returns(ast_matchers::isInteger());
+ }
+
+ template <typename... Types>
+ void registerMatchersImpl(ast_matchers::MatchFinder *Finder,
+ Types... Params) {
+ // We assume all the checked APIs are C functions.
+ auto FuncDecl = std::bind(ast_matchers::functionDecl,
+ ast_matchers::isExternC(), Params...);
+ Finder->addMatcher(
+ ast_matchers::callExpr(
+ ast_matchers::callee(FuncDecl().bind(FuncDeclBindingStr)))
+ .bind(FuncBindingStr),
+ this);
+ }
+
+private:
+ const static char *FuncDeclBindingStr;
+ const static char *FuncBindingStr;
+};
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_H
Index: clang-tidy/android/CloexecCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/android/CloexecCheck.cpp
@@ -0,0 +1,105 @@
+//===--- CloexecCheck.cpp - clang-tidy-------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CloexecCheck.h"
+#include "../utils/ASTUtils.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+namespace {
+// Helper function to form the correct string mode for Type3.
+// Build the replace text. If it's string constant, add <Mode> directly in the
+// end of the string. Else, add <Mode>.
+std::string buildFixMsgForStringFlag(const Expr *Arg, const SourceManager &SM,
+ const LangOptions &LangOpts,
+ const char Mode) {
+ if (Arg->getLocStart().isMacroID())
+ return (Lexer::getSourceText(
+ CharSourceRange::getTokenRange(Arg->getSourceRange()), SM,
+ LangOpts) +
+ " \"" + Twine(Mode) + "\"")
+ .str();
+
+ StringRef SR = cast<StringLiteral>(Arg->IgnoreParenCasts())->getString();
+ return ("\"" + SR + Twine(Mode) + "\"").str();
+}
+} // namespace
+
+const char *CloexecCheck::FuncDeclBindingStr = "funcDecl";
+const char *CloexecCheck::FuncBindingStr = "func";
+
+void CloexecCheck::insertMacroFlag(const MatchFinder::MatchResult &Result,
+ const StringRef MacroFlag,
+ const int ArgPos) {
+ const auto *MatchedCall = Result.Nodes.getNodeAs<CallExpr>(FuncBindingStr);
+ const auto *FlagArg = MatchedCall->getArg(ArgPos);
+ const auto *FD = Result.Nodes.getNodeAs<FunctionDecl>(FuncDeclBindingStr);
+ SourceManager &SM = *Result.SourceManager;
+
+ if (utils::exprHasBitFlagWithSpelling(FlagArg->IgnoreParenCasts(), SM,
+ Result.Context->getLangOpts(),
+ MacroFlag))
+ return;
+
+ SourceLocation EndLoc =
+ Lexer::getLocForEndOfToken(SM.getFileLoc(FlagArg->getLocEnd()), 0, SM,
+ Result.Context->getLangOpts());
+
+ diag(EndLoc, "%0 should use %1 where possible")
+ << FD << MacroFlag
+ << FixItHint::CreateInsertion(EndLoc, (Twine(" | ") + MacroFlag).str());
+}
+
+StringRef CloexecCheck::getSpellingArg(const MatchFinder::MatchResult &Result,
+ int N) const {
+ const auto *MatchedCall = Result.Nodes.getNodeAs<CallExpr>(FuncBindingStr);
+ const SourceManager &SM = *Result.SourceManager;
+ return Lexer::getSourceText(
+ CharSourceRange::getTokenRange(MatchedCall->getArg(N)->getSourceRange()),
+ SM, Result.Context->getLangOpts());
+}
+
+void CloexecCheck::replaceFunc(const MatchFinder::MatchResult &Result,
+ StringRef WarningMsg, StringRef FixMsg) {
+ const auto *MatchedCall = Result.Nodes.getNodeAs<CallExpr>(FuncBindingStr);
+ diag(MatchedCall->getLocStart(), WarningMsg)
+ << FixItHint::CreateReplacement(MatchedCall->getSourceRange(), FixMsg);
+}
+
+void CloexecCheck::insertStringFlag(
+ const ast_matchers::MatchFinder::MatchResult &Result, const char Mode,
+ const int ArgPos) {
+ const auto *MatchedCall = Result.Nodes.getNodeAs<CallExpr>(FuncBindingStr);
+ const auto *FD = Result.Nodes.getNodeAs<FunctionDecl>(FuncDeclBindingStr);
+ const auto *ModeArg = MatchedCall->getArg(ArgPos);
+
+ // Check if the <Mode> may be in the mode string.
+ const auto *ModeStr = dyn_cast<StringLiteral>(ModeArg->IgnoreParenCasts());
+ if (!ModeStr || (ModeStr->getString().find(Mode) != StringRef::npos))
+ return;
+
+ const std::string &ReplacementText = buildFixMsgForStringFlag(
+ ModeArg, *Result.SourceManager, Result.Context->getLangOpts(), Mode);
+
+ diag(ModeArg->getLocStart(), "use %0 mode '%1' to set O_CLOEXEC")
+ << FD << Mode
+ << FixItHint::CreateReplacement(ModeArg->getSourceRange(),
+ ReplacementText);
+}
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/android/CMakeLists.txt
===================================================================
--- clang-tidy/android/CMakeLists.txt
+++ clang-tidy/android/CMakeLists.txt
@@ -2,8 +2,10 @@
add_clang_library(clangTidyAndroidModule
AndroidTidyModule.cpp
+ CloexecCheck.cpp
CloexecCreatCheck.cpp
CloexecFopenCheck.cpp
+ CloexecMemfdCreateCheck.cpp
CloexecOpenCheck.cpp
CloexecSocketCheck.cpp
Index: clang-tidy/android/AndroidTidyModule.cpp
===================================================================
--- clang-tidy/android/AndroidTidyModule.cpp
+++ clang-tidy/android/AndroidTidyModule.cpp
@@ -12,6 +12,7 @@
#include "../ClangTidyModuleRegistry.h"
#include "CloexecCreatCheck.h"
#include "CloexecFopenCheck.h"
+#include "CloexecMemfdCreateCheck.h"
#include "CloexecOpenCheck.h"
#include "CloexecSocketCheck.h"
@@ -27,6 +28,8 @@
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
CheckFactories.registerCheck<CloexecCreatCheck>("android-cloexec-creat");
CheckFactories.registerCheck<CloexecFopenCheck>("android-cloexec-fopen");
+ CheckFactories.registerCheck<CloexecMemfdCreateCheck>(
+ "android-cloexec-memfd-create");
CheckFactories.registerCheck<CloexecOpenCheck>("android-cloexec-open");
CheckFactories.registerCheck<CloexecSocketCheck>("android-cloexec-socket");
}
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